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Full text of "The manufacture and properties of iron and steel"

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WELDING.                                                 403
profitable 10 quote from Holley the following conclusions concerning iron :*
"(1) None of the ingredients .except carbon in the proportions present seems to very notably affect the welding by ordinary methods. [The masinmm percentages were P, .317; Si, .321; Mn, .097; S, .0.15; Chi, .43; M, .34; Co, .11; Slag, 2.262.]
"(2) The welding power by ordinary methods is varied as much by the amount of reduction in rolling as by the ordinary differences in composition.
"(3) The ordinary practice of welding is capable of radical improvement, the most promising field being in the direction of welding in a non-oxidizing atmosphere."
SEC. XlXb.—Tensile tests on welded bars.—The allowable contents of metalloids given in the foregoing synopsis will show the gulf that separates iron from steel, and this will be further indicated by Table XIX-A, which gives tests on welded steel bars of different 'compositions, the investigation having been conducted under my own direction. The lack of certainty and regularity is evident, and yet the smiths were men of long experience in handling steel, and fully understood that individual results were to be compared. The bars were of a size most easily heated and quickly handled, but the record is extremely unsatisfactory.
In the rounds, each workman has at least one bad weld against him, while there is only one heat which gave uniformly good results. Picking out the worst individual weld of each workman, blacksmith "A" obtained only 70 per cent, of the value of the original bar, "B"' 54 per cent., "C" 58 per cent., and "D" only 44 per cent. The forging steel showed one weld with only 48 per cent., the common soft steel 44 per cent., while even the pure basic steel gave one test as low as 59 per cent. In some cases where the break took place away from the weld, the elongation was nearly up to the standard, this being true of the four tests of the seventh group, and it should be noted that this metal contained .35 per cent, of copper, but in the other pieces the stretch was low and the fracture so silvery that it was plain the structure of the bar had been ruined. In most cases where the test-bar broke in the weld, the pieces parted at the surfaces of contact, showing that no true union had taken
* The Strength of Wrought-Iron as Affected by its Composition and by its Reduction in Boiling,   Trans. A. I. M. E., Vol. VI, p. 101.............